1. Field of the Invention
This invention relates to a magnetic recording medium, such as a magnetic tape or a magnetic disk. More particularly, it relates to a magnetic recording medium in which an amine salt of carboxylic acid is used as the lubricant.
2. Prior Art
With a so-called metal thin film type magnetic recording medium, in which a magnetic metal material is deposited, such as by evaporation, on a non-magnetic base so as to be used as a magnetic recording layer, or a so-called coated type magnetic recording medium, in which a magnetic paint containing extremely fine magnetic particles and the resin binder are coated on a non-magnetic base so as to be used as a magnetic layer, there are presented problems in that the effective contact area of the magnetic layer with sliding members such as the guide roller or the magnetic head is increased due to the high smoothness of the surface of the magnetic layer thus giving rise to increased coefficient of friction and so-called sticking as well as poor running properties and durability.
In order to obviate these problems, attempts have been made to use various lubricants, such as higher fatty acids or their esters, which are contained in or top coated on the magnetic layers of the magnetic recording medium to lower the coefficients of friction.
Meanwhile, the lubricants used with the magnetic recording medium are demanded, by their nature, to have special properties, which cannot be met with the lubricants in current use.
Thus the lubricants used with the magnetic recording medium are required i) to have excellent low temperature characteristics so as to exhibit lubricating effect to a certain extent when used in cold climate; ii) to be able to be coated to an extremely small thickness to meet the spacing requirements with respect to the magnetic head and to exhibit sufficient lubricating properties; and iii) to be able to be used for prolonged time or to have long service life with sustained lubricating properties.
However, higher fatty acids and esters thereof currently in use tends to become frozen and solidified at lower temperature, such as 0.degree. C. or lower, unusuable as the lubricant or low in durability.
Thus the magnetic recording medium frequently exhibits poor runnability, abrasion resistance and durability due to inadequacy of the lubricant used with the recording medium.